Solar cells with p-type and n-type carbon nanotubes have been proposed.
Conventionally, in the manufacture of these carbon nanotubes, carbon nanotubes are grown on the surface of a substrate by, for example, thermal chemical vapor deposition (may be called thermal CVD); meanwhile, the surface is doped with Group III or V elements of the Periodic Table of the Elements. Specifically, the elements are deposited on the surface of a carbon nanotube (For example, see Japanese Patent Laid-Open No. 2011-44511).